Compared with the placebo group (n = 197), which experienced an average 25(OH)D decrease of 4.5 nmol/L by study end, the treatment group (n = 202) had an average increase of 56.1 nmol/L. Furthermore, patients who received vitamin D supplementation had a significant decrease in serum PTH, an increase in calcium, and a slight but significant decrease in PINP (P <.01).

Reduction of PINP was more significant in treated individuals who had baseline PTH levels >6.5 pmol/L and showed a posttreatment decrease. These individuals also experienced significantly reduced levels of CTX-1 and increased sclerostin.

Several limitations were noted for this study, including an absence of data on participants’ calcium intake.